Printing cellulose acetate fabrics with oxidation dye pastes comprising an alcohol and thickened with methyl cellulose



Patented July 11, 1950 Henry Charles Olpin and Tom J ackson, Spondon,. I

near Derby, England, assignors to ,Cclanese Corporation of America, a corporation of Delaware N Drawing. vApplication July 3, 1947, Serial No. 759,002. In Great Britain July'17, 1946 s Claims. (Cree-'33 This invention relates to the colouration of textile materials and is more particularly concerned with the production of local colourations upon textile materials consisting of or containing fibres of cellulose acetate.

U. S. application S. No. 592,725, filed May 8, 1945, describes the colouration of textile materials, particularly those of cellulose acetate fibres, by the application, especially by printing methods, of a colouring composition comprising a solution of a dye in an aqueous lower aliphatic alcohol of at least strength thickened with a water-soluble methyl cellulose. Methyl cellulose is a very satisfactory thickening agent for aqueous compositions of this kind, whereas the usual thickening agents employed in the textile printing art, for example, gum tragacanth, gum arabic, British gum and similar materials are unsuitable for the thickening of the aqueous alcohol preparations so as to render them capable of satisfactory application by printing methods. According to the present invention, preparations containing, in an aqueous lower aliphatic alcohol of at least 50% strength by weight, compounds which can be converted into dyes on a textile material are thickened with water-soluble methyl cellulose to render them suitable for application to textile materials by mechanical impregnation methods, particularly printing.

The invention is especially useful in connection with the production of aniline black type'colourations on cellulose acetate textile materials. By "aniline black type colourations is meant the blacks and other dark colourations obtainable by oxidising an aromatic amine on the material. Examples of such oxidisable amines are aniline, p-aminodlphenylamine, p-phenylenediamine and p-aminophenol. For this purpose, the aniline or other oxidi'sable aromatic amine is, in accordance with the invention, applied to the textile material in an aqueous lower aliphatic alcohol of at least 50% strength, the said aqueous alcohol being thickened with the methyl cellulose. Very good results are obtained with aqueous alcohol of from to strength, although stronger or weaker alcohol may be used.

The water-soluble methyl cellulose can be made by the action of methyl chloride on alkali celluloses which have been suitably aged. Particularly useful are methyl celluloses having a methoxy content of 22% to 30%, and especially those which yield aqueous solutions of high vis cosity, for example products which in a 2% aqueous solution at 25 C. have a viscosity of at least centipoises. Anespecially useful-product; is I amethyl cellulose having a methoxy content of 26% to-2 7% and a viscosity of 350 to 500 centipoises measured in 2% aqueous solution at 25 C. Using .such high viscosity methyl cellulose it is possible to obtain the thickening effect requisite for printing with 1% to 2% based on the weight of the alcohol /water mixture.

- The alcohol is preferably ethyl alcohol, although methyl-alcohol, propyl alcohol or isopropyl alcohol can be employed. Mixtures of these alcohols may also be used, for example a 'mixtureof ethyl and methyl alcohol such as is present in methylated spirit.

. The thickened preparations preferably contain a softening agent for cellulose acetate. For this purpose, water-soluble thiocyanates are very suitable, for example, ammonium thiocyanate and sodium, potassium and other alkali metal thiocyanates. The preparation may, for instance, contain from 3% to 8% of one of these thiocyanates, particularly ammonium thiocyanate.

As is usual in the production of aniline black type colourations on textile materials the oxidation of the aniline or other oxidisable aromatic compound 'is'preferably effected by means of an oxidising agent included in the preparation containing the aromatic compound. A chlorate is the preferred oxidising agent. Chlorates are substantially inactive in the preparations in the cold but become active when steamed on textile materials. Oxidation catalysts may also be, and preferably are, included in the compositions. The catalyst may for instance be a salt of copper, e. -g. copper sulphate or cupric chloride, or a ferrocyanide e. g. potassium ferrocyanide or a vanadate, e. g. ammonium vanadate, or a salt of cerium, for example cerium chloride.

' After the compositions containing the oxidisable aromatic compounds have been applied to the materials the latter are aged or steamed in order to eliect development of the desired colourations...

Particularly good results can be obtained upon cellulose acetate textile materials by using aniline alone or p-aminodiphenylamine in conjunction with aniline. In this way, excellent black prints can be obtained. Moreover, the compositions can be-printedalongside the coloured printing pastes described in U. S. application S. No. 592,725, filed May 8, 1945, a subsequent steaming serving both-to develop the black and to fix satisfactorily the colour print.

In thecase of using aniline as the oxidisable aromatic amine the composition preferably contains a mineral acid in quantity chemically equivalent to the aniline and also some additional acid which may be eithermineral acid or organic acid. The mineral acid can be hydrochloric acid. It is usually convenient to incorporate the aniline in the composition in the form of a mineral acid salt and particularly in the form of aniline hydrochloride. The organic acid can be formic acid, acetic acid or lactic acid.

A second class of organic compounds capable of being converted into dyes on textile materials and. which can be applied in accordance with the present invention is that of thesalts'of acidsulphuric esters or of acid phosphoric esters of leuco compounds of vat dyes. In this case the conversion of the sulphuric or phosphoric ester Qfthe leuco vat dye into the parent vat dye onthe ma.- terial is conveniently eifected by means of an acid oxidising treatment, for example by treatment with an acidified solution of a nitrite. If desired, a nitrite may be incorporatedin the composition applied to the textile material and the conversion of the sulphuric ester or phosphoric ester of the leuco vat dye into the parentvat dye effected by treating the materials carryingthe compositions with an aqueous acid. Examples of such acid sulphuric esters of leuco vat dyes are the acid sulphuric esters of leuco dimethoxy dibenzanthrone, leuco 4:4'-dimeth-yl-6:(ii-dichlorthioindigo and leuco 6:6-.diethoxy-thioindigo.

, Other compounds capable of conversion into colouring matters upon textile materials and which can be applied by the process of the present invention are diazotisable amines and azo coupling components. Thus, amine may be applied in the aqueous alcohol thickened with the methyl cellulose and subsequently diazotised on the material and coupled with an azo coupling component.

Examples of such diazotizable, amines are 4-nitroaniline, 4-nitro-2-aminotoluene, --nitro 2- aminoanisole, aminoazobenzene and 4-nitro-4- amino-2' :5-dimethoxyazobenzene. Examples of coupling components which can be employed are para coupling N-dialkyl anilines, e. g. N-diethyl aniline, N-diethylmetatoluidine, N-di-(beta-hydroxyethyl)-metatoluidine and meta-acetylamino-N-di-(beta-hydroxyethyl)-aniline, aryl amides of 2:3-hydroxynaphthoic or other aromatic hydroxy carboxylic acids, e. g. the anilide of 2:3- hydroxynaphthoic acid, and acyl-acetyl derivatives of aromatic amines such as the well-known diaceto-acetylortho-toluidine. Again, a coupling component may be applied to the material in aqueous alcohol thickened with methyl cellulose and thereafter converted into an azo dye upon'the material by treating the latter with an appropriate diazo compound. Further and more particularly in the case of cellulose acetate textile material both an azo coupling component and diazotisable amine may be applied together in the aqueous alcohol thickened with methyl cellulose and the material thereafter treated so as to effect diazotisation of the amine and coupling of the resulting diazo compound with the coupling component upon the material.

For example para-nitro-aniline or other diazotizable aromatic amine may be applied together with beta-naphthol in this way and the material subsequently treatedto effect diazotization of the amine and coupling of the resultingdiazo compound with the beta-naphthol. When both diazotisable amine and coupling component are applied together to the materialthe development of the azo' dye can be accomplished by treating the material with an acidified nitrite solution fola diazotisable 4 lowed by an alkaline treatment. Finally, the material should be given a hot soaping treatment in order tobring the azo dye into the desired physical form upon the material.

As already indicated, the process of the invention is of especial value for the production of colourations upon textile materials consisting of or containing fibres of cellulose acetate though it can be used in the case of textile materials of other, fibres, e. g. natural or regenerated cellulose, or natural silk.

The invention is illustrated by the following examples:

Example 1 A methyl cellulose paste is prepared consisting of 69% of methylate spirit, 23% of water, 6% of ammonium 'thiocyanate, and 2% of methyl cellulosefiall by weight).

The following preparations (a), (b), and (c) are then made up:

6,605 gms. of the above methyl cellulose paste, 500 gms. of p-aminodiphenylamine,

gms. of aniline hydrochloride,

425. gms. of acetic acid,

350 gms. of lactic acid (50% strength).

of sodium chlorate, of water.

375 gms. 625 gms.

.250 gms. of aluminium chloride solution, 52?

Twaddell,

37.5 gms. of cerium chloride,

212.5 gms. of water.

The three preparations (a), (b) and (c) are mixed together immediately before being required for printing and 500 gms.. of sodium lactate is added. The mixtureso obtainedis printed on cellulose acetate. fabric which is thereafter dried and given two 15-minute steamings at 225 F. It is then-washed forhalf an hour incold water, soaped for 20 minutesin a 2 -gms. per litre soap'solutionat 50 C., and finally washed, dried and finished as usual. Very good blacl: prints are thus obtained.

Example 2 The following preparations (a) and (b) are made up, all parts being by weight:

Water 10 Solutions (a) and (b) are mixed together-and immediately printed on to celluloseacetate fabric. The latter is then dried and steamed for 20minutes at 107.2 0. (225 F.). It is then treated for 5 minutes at 50 C. in an aqueous bath containing 5 grammes per litre ofv sodium-bichromate and 5 cos. per litre of glacial acetic acid. The material is then rinsed, soaped for 10 minutes at 60C. and finally rinsed and dried. Excellent black prints are thus obtained.

Example 3 A thickening is prepared of the following composition, the parts referred to being by weight:

I Parts Methylated spirit 70 Water -1 24 Ammonium thiocyanate 4 Methyl cellulose 2 5 parts of the sodium salt of the acid sulphuric ester of leuco dimethoxy-dibenzanthrone (commercial product) and 3 parts of sodium nitrite are dissolved in 92 parts of the above-mentioned thickening. The solution is then printed on a cellulose acetate fabric and the latter steamed for minutes at 106 C. (223 F.). The printed material is then developed by a treatment for 3 minutes at 75-80 C. in grammes per litre aqueous sulphuric acid. After development, the printed material is washed, soaped at 70 C. and finally washed and dried. Excellent green prints are thus obtained.

The printing operations referred to above can be carried out with engraved rollers. Again screen printing methods can be employed. In the latter case the fabric to be printed is advantageously stuck down on to a table, e. g. with a water soluble gum, and then printed in sections with the aid of the stencil screen. A resilient bed for the fabric is desirable and the surface of this should be of material which is not substantially affected by the printing paste. This resilient bed can consist of a felt blanket covered with rubberised fabric or fabric which carries a coating of a polyvinyl chloride composition. A very useful fabric of the latter kind can be made by sizing a cotton fabric with an aminoplast, for example a condensation product from formaldehyde and urea, thiourea, or melamine, or other amino-triazine, so as to give the fabric a smooth surface and then applying a coating of polyvinyl chloride. The latter preferably contains a plasticiser, for example highly chlorinated parafiin wax or one of the wax-like bodies obtainable by chlorinating diphenyl or naphthalene. Thus cotton madapolam can be sized with a water soluble urea-formaldehyde or melamine-formaldehyde condensation product, and hot-calendered to render the condensation product insoluble in water and give the fabric a smooth surface; the fabric is then coated with a dope consisting of 200 parts of methyl-ethyl ketone, 15 parts of chlorinated parafiin wax (containing about 50% of chlorine), and parts of acetone-insoluble polyvinyl chloride (made by polymerizing an emulsion of vinyl chloride and spray-drying the product). The methyl-ethyl-ketone is then removed by evaporation. A coating of about 300 grams of solids per square yard of fabric is very satisfactory.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process for the coloration of cellulose acetate textile material, which comprises impregnating the material with a solution of a chlorate and an aromatic amine in an aqueous lower aliphatic alcohol of at least 50% strength by weight thickened with a water-soluble methyl cellulose having a methoxy content of 22-30% and a viscosity of at least centipoises as measured in a 2% aqueous solution at 25 C., said alcohol being of the series CnH2n+1OH where n is from 1 to 3, and thereafter steaming the material to oxidize the amine to an aniline black type coloration on the material.

2. Process for the production of black prints upon cellulose acetate textile fabrics, which comprises printing the fabrics with a composition comprising paraamino-diphenylamine, aniline hydrochloride, sodium chlorate and an oxidation catalyst together in a solution in aqueous ethyl alcohol of at least 50% strength thickened with a water-soluble methyl cellulose having a methoiq content of 22-30% and a viscosity of at least 150 centipoises as measured in a 2% aqueous solution at 25 C., and thereafter steaming the materials to effect the formation of an aniline black type colouration on the printed portions of the material.

3. Process for the production of black prints on cellulose acetate textile fabric, which comprises printing the fabric with a composition comprising aniline hydrochloride, formic acid, sodium chlorate and an oxidation catalyst together in solution in aqueous ethyl alcohol of at least 50% strength thickened with; water-soluble methyl cellulose having a methoxy content of 22-30% and a viscosity of at least 150 centipoises as measured in a 2% aqueous solution at 25 C., and thereafter steaming the material to effect formation of aniline black on the printed portions of the material.

HENRY CHARLES OLPIN. TOM JACKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Textile Printing, by Knecht and Fothergill, Charles Griffin and Co., London, 3rd edition, 1936, pages 138, 139. (Available in Div. 43 of Patent Ofllce.) 

1. PROCESS FOR THE COLORATION OF CELLULOSE ACETATE TEXTILE MATERIAL, WHICH COMPRISES IMPREGNATING THE MATERIAL WITH A SOLUTION OF A CHLORATE AND AN AROMATIC AMINE IN AN AQUEOUS LOWER ALIPHATIC ALCOHOL OF AT LEAST 50% STRENGTH BY WEIGHT THICKENED WITH A WATER-SOLUBLE METHYL CELLULOSE HAVING A METHOXY CONTENT OF 22-30% AND A VISCOSITY OF AT LEAST 150 CENTIPOISES AS MEASURED IN A 2% AQUEOUS SOLUTION AT 25*C., SAID ALCOHOL BEING OF THE SERIES CNH2N+1OH WHERE N IS FROM 1 TO
 3. AND THEREAFTER STEAMING THE MATERIAL TO OXIDE THE AMINE TO AN ANILINE BLACK TYPE COLORATION ON THE MATERIAL. 